Compass



Jan. 16, 1934. c G. LARSON COMPASS Filed May 19, 1932 a x M w 3 B o J w3 a r w patente& `Fan. 1934 PATENT OFFiCE 1,943,921 coM ss Cari G.Larson, Attleboro, Mass., assignor to Larson Tool and Stamping Company,a corpcration of Massachusetts Application May 19,1932. Serial No.612,179

7 Claims.

This invention relates to a compass and has for one of its objects toprovide a Construction which will prevent play about its pivotalconnecting parts and be rigid against usual operating strains that moreaccuracy may be obtained in its use.

Another object of the invention is the provision of a construction whichmay be assembled with greater speed and accuracy that the cost ofproducing the same may be reduced.

Another object of the invention is the provision of an assembly, theparts of which 'cannot become accidentally detached and lost.

A further object of the invention is the pro- Vision of a reslientspring which will give greater fiexibility of action of the parts andyet one which may be used for positioning the parts to hold them indesired relation when assembled.

With these and otherobjects in View, the in- 'Vention consists ofcertain novel features of Construction, as will be more fully described,and particularly pointed out in the appended claims.

In the accompanying drawing:

Fig. 1 is a side elevation of my compass.

5 Fig. 2 is aview similar to Fig. 1 showing the same in partially spreadposition with parts broken away showing'the branches of the compasspartly in section.

Fig. 3 is a perspective View of the yoke memi ber of the compass.

Fig. 4 is a perspective View of the assembly of the yoke, threadedadjustment member and nut.

Fig. 5 is a side elevation of a fragmentai portion of the compass withthe lower part of the branches broken away.

Fig. 6 is a section on line 6-5 of Fig. 1.

Fig. 7 is a section on line '7--7 of Fig. 6.

Fig. 8 is a perspective View of one of the branches or legs of thecompass.

Fig. 9 is a perspective View showing a modified adjustment member in thepermanently assembled suit.

In the formation of compasses, it is desirable that the compass shouldmaintain a certain rigidity about its pivotally connected parts so thataccuracy may be had in movements which it is adapted to perform. Also,it is desired that the compass be so formed that the parts will notbecome easily separated and lost or mislaid, and

in order to accomplish these results, I have provided a special unitassembly which is mounted upon the pivot pin connecting the branch armsof the device and when so mounted cannot be detached therefrom to becomelost, and by an & improved provision of yoke I cause the arms tobodiment of this invention illustrating the preferred means by whichthese advantageous results may be accomplished.

With reference to the drawing, 10 designates one of the branches or legsof the compass pro- Vided with a spur point 11, and 12 the other branchor leg of the compass provided with a pencil 13 held in by theresiliency of the hollow leg or a spur point such as 12 may be providedif desired. These branches are both ormed of hollow sheet stock and areeach provided with laterally extending portions 14 and 15 which are eachpressed inwardly as at 18 and 19 from the opposite sides thereof to formcircular cups or recesses which nest one within the other and throughopenings 16 in the bottom of these depressions there extends a pivot pin17. The telescoping of the parts 14 and 15 and the nesting of thedepressions assist in bracing and stiffening the b'anches or legs intheir pivotal oo movement about the pin 17. In each of the branchesthere is a notch 20 having generally parallel side edges 21 and a bottomedge 22 at right angles thereto.

A spring 23 is coiled a plurality of times about the pivot pin 17 inorder to give easier action and greater flexibility with its endportions 24 and 25 extending into each of the hollow or tubular branchesurging them to swing apart about the'pivot 17. Although any number ofcoils may be used I have here illustrated three bends 26 on the upperside of the pivot pin 17.

In order to control or govern the movement of the branches of thecompasses I have provided a unit asembly as shown in Fig. 4, the sameconsists of an adjusting screw 27 with an integral head 28, a nut 29threadingly engaging the threads of the member 27 and a yoke 30 throughwhich the nut applies pressure to the branches of the compass.

The yoke member is formed from sheet stock and is folded as at 37providing a generally cylindrical portion 38 to receive the shank 27 ofthe adjustable member with the parts 39 of this yoke lying more or lessclosely together as shown in Fig. 4, while the free ends 40 are eachspread or branched outwardly as illustrated in Figs. 3 and 4, and thenbent inwardly to form lips 41 so as to provide a generally rectangularform with the inherent spring of the stock forcing the same outwardly toengage the parallel edges 21 of the notch 20 and. with the lips 4:1resting against the bottom edge 22 of this notch at spaced points. ThusI provide a two-point bearing or point of rest of the yoke on each ofthe branches of relatively wide hearing surfaces which rigidly supportthe same. The increase of the bearing surfaces of the free ends of onthe bottom edges of the notches 20 steadies the lower portions of theyoke 30 and adds greatly to the rigidity of the joint. As pressure isapplied by means of the nut 29 the yoke will be forced downwardly toforce the branches about the pivot 17 against the tension of the spring23 to obtain the desired adjustment of the parts.

This unit shown in Fig. 4 is assembled by first placing the nut inposition on the threaded shank of the member 27 and then positioning theyoke thereon as illustrated in Fig. 4 after which the end of the member27 is flattened as at 31, thus spreading the same and preventing removalof the parts so assembled, after which an opening 32 is pierced in thisflat portion to receive the pivot pin 17 pivotally joining the branchesof the compass together.

In the illustration which I have shown, in order that the parts may becentralzed, the fiattened portion 31 is offset with.` reference to thecenter of the shank 27 as illustrated in Fig. 6 so that the coils orbends 26 of the spring are received two on one side and one on the otherside of this member in its position on the pivot 17. By this arrangementthe member is held in desired centi' ized position by means of the bendsof the spring between the two depressions 18 and 19 of the compasses.

In Fig. 9 I have illustrated a modified form of the lower end of thescrew in which the parts are separated to form a spaced hearing portionand one to centralize itself with reference to the arms by reason of itsbeing offset on both sides of its center and will thus receive one ofthe bends of the spring between these bifurcated portions and one oneach side to assist in steadying and providing a balanced Construction.

The foregoing description is directed solely to- Wards the Constructionillustrated, but I desire it to be understood that I reserve theprvilege of resorting to all the mechanical changes to which the deviceis susceptible, the invention being defined and limited only by theterms of the appended claims.

I claim:

1. An instrument comprising two branches, a pivot pin .for connectingsaid branches together, means for adjusting and maintaining saidbranches in desired position including a yoke having spaced apart, flatlip portions in engagement with each of said branches at two spacedpoints thereof to steady the same.

2. An instrument comprising two branches, a pivot pin for connectingsaid branches together, a threaded member extending outwardly from saidpivot, and a yoke enbracing said threaded member and having spacedapart, flat lip portions providing spaced points of engagement with eachof said arms.

3. An instrument comprising two branches, a pivot pin for connectingsaid branches together, means for adjusting and maintaining saidbranches in desired position including a yoke having engagement witheach of said branches at two spaced points to steady the same, said yokebeing formed of sheet stock and being partly folded upon itself with thefolded portions in contact, and said portions being branched outwardlyand spaced apart at their free edges.

4. An instrument comprising two branches, a pivot pin for connectingsaid branches together, means for adjusting and maintaining saidbranches in desired position including a yoke having engagement witheach of said branches at two spaced points to steady the same, said yokebeing formed of sheet stock and being partly folded upon itself with thefolded portions in contact, and said portions being branched outwardlyand spaced apart at their free edges and with their ends turned inwardlytoward each other.

5. An instrument comprising two branches, a pivot pin for connectingsaid branches together, said branches each having a square sided notchin the upper end and means for adjusting said branches about the pivotincluding a yoke having spaced apart fiat lip portions engaging the V .a

opposite side edges of each notch at points spaced apart.

6. An instrument comprising two branches, a pivot pin for connectingsaid branches together,

said branches each having a square sided notch in the upper end andmeans for adjusting said branches about the pivot including a yokehaving resiliently spaced apart fiat lip portions engaging the oppositeside edges of each notch with resilient pressure at points spaced apart.

7. An branches, a pivot pin connecting said branches together and aspring having a plurality of coils about said pin with an end portionextending into each of said branches, an adjusting screw having an endportion offset from the longitudinal center of said pin and engagingsaid pin, said offset portion dividing said pin into two instrumentcomprising two hollow I' unequal parts, one part receiving more of saidg coils than the other by reason of said offset whereby said parts maybe maintained in generally balanced relation.

CARL G. LARSON.

